Durable-press cotton textiles and method of making same

ABSTRACT

DURABLE-PRESS COTTON TEXTILES ARE PREPARED BY A CHEMICAL PROCESS WHEREIN METHACRRYLIC ACID IS GRAFTED ONTO THE TEXTILE AND THE GRAFTED TEXTILE IS SUBSEQUENTLY CROSSLINKED WITH DIMETHYLOLDIHYDROXYETHYLENEUREA (DMDHEU) WITHOUT THE USE OF THE USUAL CATALYSTS SUCH AS ZINC NITRATE. THE TEXTILE IS DRIED TO A MOISTURE CONTENT OF ABOUT 0.5%, IRRADIATED IN AN INERT ATMOSPHERE TO A DOSAGE OF 0.5-1 MEGARAD, IMMERSED IN A SOLUTION OF METHACRYLIC ACID, METHANOL AND WATER, WASHED, DRIED THEN IMMERSED IN A SOLUTION OF DMDHEU, WATER AND A WETTING AGENT, DRIED AND CURED AT 160*C.

United States Patent 1 1 2 6,827,858 DURABLE-PRESS'CO'ITON TEXTILES AND ':-J ;,.METHOD OF-MAKING SAME Ge they .A. .Byrne, Hadd ingtimy/Scotland, and Jett C. Arthur, Jr., Metairie,'La., assignprs to the United States of Americans represented by the, Secretary of Agncult'u're 1 'No DrawinguFiled Apr." '27, 1972, Ser. No. 248,180 Int."Cl.-C08f 1/24,"3/46';'D06m 13/20 US. Cl; 8-184 a i 2 Claims "ABSTRACT on THE DISCLOSURE Durable-presscotton textiles are prepared by a chemical process wherein methacrylic acid is grafted onto the textile and the grafted textile is'subsequently'crosslinked with dimethyloldihydroxyethyleneurea (DMDHEU) without the use of the usual catalysts such as zinc nitrate. The textile is dried to a moisture content of about. 0.5 irradiated in aninertsatmosphere to a dosage of .0.51 megarad, immersed in a solution of methacrylic acid, methanol and water, washed, dried thenimmersed in a solution of DMDHEU, water and a wettingtagent, dried and cured at 160 C.

A non-exclusive, irrevocable, royalty-free license in the invention herein described throughout the world for all purposes of the United S'tatesGover'nment, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates-tochemical treatments of cotton and other cellulosic textiles. More specifically, this invention'r'elate's to an improved chemical process comprising a sequence of'ste'ps useful in the preparation of durablepress fabric'swherein (I) a cotton or other cellulosic poly(vinyl) graft copolymer fabric is prepared by a freeradical'initia'td graftcopolymerization process, and (2) the"cellulosic-poly(vinyl)copolymer fabric is submitted to a crosslinking reaction without catalyst, to yield durable-presscellulosic-textileproducts without the usual losses in breaking strength and'tearing strength which generally are obtained in durable-pressproducts;

The main objectofithis invention .is to provide improvement in the chemical processing which yields durable Press fabrics.

Another object of thisinven tion'is to provide the fabrics produced by the improvements indicated.

In the prior art cotton-='fabrics-are commonly crosslinked with reagents such asdirnethyloldihydroxyethyleneurea to obtain durable-press 'cotton' textile products. Catalysts, such as zinc nitrate, are included in the crosslinking lformulations "to "obtain the"'-crosslinked textiles with good 3,827,858 Patented Aug. 6, 1974 found that the durable-press properties of the derived crosslinked cotton copolymer textile products are improved over those of crosslinked cotton textile products in that the wrinkle recovery properties are improved without large decreases in breaking and tearing strengths of the cotton textile products. Furthermore, we have now found that if catalysts are excluded in the solution containing the crosslinking reagent that the wrinkle recovery properties of the crosslinked cotton copolymer textile products are improved over those of catalyzed, crosslinked cotton textile products, while the other properties, such as breaking strengths and tearing strengths of the derived durable-press cotton textile products are about the same for both crosslinked cotton copolymer textile products and crosslinked cotton textile products.

Samples of cotton fabrics used were printcloth (about 3.1 ounces per square yard, 86 x 86 thread count) and were commercial grey cloths which had been enzymatically desized, alkali scoured, and peroxide bleached on a pilot plant scale. Samples of the cotton fabrics were dried overnight in a vacuum oven at C. to a moisture content of about 0.5% and then irradiated at ambient temperature (about 25 C.) in a nitrogen atmosphere in sealed glass tubes with cobalt-60 irradiation, a convenient source of radiation, to a dosage of about one-half to one megarad to produce long-lived free radicals on the cellulose molecules which comprise the cotton. Radiation-activated cotton fabric (about 1.5 parts), now containing free radical sites on the cotton cellulose molecule, was immersed in a solution of 1.5 to 3 parts of vinyl monomer, such as methacrylic acid, 2.5 to 50 parts of water, and 47.5 to 0 parts of methanol which had been purged with nitrogen, at 25 C. for the desired reaction time from about 15 to 30 minutes to yield a cotton-poly(methacrylic acid) copolymer fabric with the desired add-on of poly(methacrylic acid) from about 7 to 49%. The cotton copolymer fabric was washed with a solution of methanol-water (equal parts) to remove unreacted vinyl monomer and then air-dried at 25 C. The add-on of poly(methacrylic acid) was determined as the increase in weight of the cot- 1 ton copolymer fabric over that of an untreated cotton fabric. A typical reaction time and poly(methylacrylic acid) add-on from 2.5 parts of water, 47.5 parts of methanol, and 1.5 parts i'riethacrylic acid onto 1.5 parts of cot- 7 ton fabric which had been pre-i rradiated to a dosage of wrinkle recovery properties.The Wet impregnated fabrics The presenttirrvention discloses; a distinct improvement.

in the durable-press properties of cotton textiles by the preparations of cotton gra f tcopblyiner's and then by cross-" linking of the cotton 'copo'lynier withthe usual crosslinking reagents, such as the aforementioned dimethyloldihydroxyethyleneurea, but without catalysts. We have now .delphia Pa. l" v V p y The followingexamples are provided to facilitate the comprehension of the invention and should not be coni one megarad was: 30 minutes and 7 percent add-on. Samfabrics were padded to a wet pick-up of with a typical crosslinking solution (comprising ;dimethyloldihy-- 'droxyethyleneurea 1.8 parts, zinc-initrate catalyst 3 parts, wetting agent 0.1 part, and water 78.9 parts). For several tests'the zinc nitrate-catalysts'were omitted from the crosslinking solu't'ion. The fabrics, paddedwith crosslinking solution,'were dried for 3 minutes at 60 C. and then cured for 6 minutes at C. The durable-press properties of the treated cotton fabrics and treated cotton copolymer fabrics were determined by standard methods i of the AmericanS ociety for Testing and Materials, Philastrued as limiting the invention in any manner whatsoever.

. ..EXAMPLES [Durables-press, crosslinked cottforgprilflmethacrylie acid) cooplymer :1 cs

Wrinkle Grafted recovery polymer Breaking Tearing angle Example add-on, strength, strength, (W+F) number percent lb. g. degrees Untreated control Crosslinked, no catalyst Crosslinked, catalyst 3 0 15 200 280 Grafted only Grafted, crosslinked, no catalyst b Grafted, crosslinked, catalyst 9 9 Determined by standard procedure, American Society for Testing and Materials, Philadelphia, Pa., ASTM Designation D1295 -60T.

h Crosslinked with dimethyloldihydroxyethyleneuree using no eatalyst. (This illustrates the process oi-the present invention.)

9 crosslinked with dimethyloidihydroxyethyleneurea using zinc nitrate catalyst.

With reference to Examples 4, 5, 6, and 7, the cottonpoly(methacrylic acid) copolymer fabrics thus prepared retained breaking strengths about equal to that of untreated cotton fabric (Example 1), showed decreases in tearing strengths, and exhibited no significant changes in wrinkle recovery angles.

With reference to Examples 8, 9, 10, 11, and 12, the crosslinked cotton-poly(rnethacrylic acid) copolymer fabric products thus prepared retained breaking strengths about equal to that of untreated cotton fabric (Example 1), and showed decreases in tearing strengths. These specific examples illustrate the results obtained when practicing the invention, and obviously Example 8 would be the preferred embodiment economy-wise. It must be noted that not catalyst was added in any of the 8-12 Examples. These copolymer fabric products showed increases in wrinkle recovery angles ranging up to 66 degrees over those of the untreated cotton fabric (Example l), and 56 degrees over the crosslinked, no catalyst fabric of Example 2.

With reference to Examples 13 and 14, the crosslinked cotton-poly(methacrylic acid) copolymer fabric products thus produced, the breaking strengths and tearing strengths of the copolymer fabric products were decreased as compared with the untreated cotton fabric of Example 1, as well as the grafted only products of Examples 4-7, and the grafted, crosslinked, no-catalys t products of Examples 8-1-2, but were about the same as the crosslinked catalyzed'fa'bric'ofExample 3. Examples l3an'd 14 yielded higher wrinkle recovery angles than all the other products illustrated. .I I a i I The invention can be easily comprehended by examination of .the textile properties of the durable-press fabric I products shown in Examples 3, 13, and .14, as compared.

with those of the durable-press-fabricproducts,shown order to obtain the desired increase in wrinkle recovery (Example 3) over that funtreated, contr ol fabric"'(Ex ample l) or "crosslinked, no catalyst fabric (Example 2), large undesirable decreases in brealdng'stre'ngth and tearing strength are concomitantlyobtainedllf'a cotton copolymer fabric was prepared and then crosslinked by the usual processes (Examples 13 and 14), desirable increases I. vH. NEWSOME, Assistant Examiner-2* 'in wrinkle recovery (Examples 13 and 14) over those of.

fabric (Example 2). It should beparticiilar' ly rioted that' this desired increase jiri "wrinkle' recovery[(Eximfiles 8-12) by the method of the instant invention wasobtained without any loss in breaking strength and, much less loss in tearingstrength than recorded ,when crosslinked fabrics prepared by the usual processes (Example 3) or even for those grafted copolymer fabrics crosslinked by the usual processes (Exan pleslii. and 14) were prepared to illustrate 'the 'desiredin'creases in wrinkle recovery in a durable-press cotton' 'product.

1. A process for preparing a durable-press cotton'fabric, which simultaneously retains high breaking strength, and 9 particularly high tearing strength with respect' to nitreated cotton, the process comprising:

(a) drying a eellulosic about 0.5%,

(b) irradiating the dry eellulosic textile with a radioactive source, in an'inert atmosphere, to'a dosage of 0.5 to 1 megarad,

(c) immersing the irradiated eellulosic textile in a solution computed to contain proportionately, includin the eellulosic textile; about w I 1.5 parts by weight of eellulosic textile, 1.5 to 3 parts by weight-of solution of meth acid, 1 I 2.5 to 50 parts by weight of water, and I 47.5 to 0 parts byweight of methanol. I I at about 25 C. for periodsabout from 15 to 30 minutes of time to give desired poly(methacrylic acid) add-on to the eellulosic textile, of about from-7% to (d) washing the unreaeted-material ofl the treated cellulosic textile with a solution of methanol and water.-

in equal parts, I I (e) drying the reacted and-washed cellulosic textile,

(f) immersing the reacted eellulosic textile in a solution computed to consist of proportio'nately about 18 parts by weight eneurea, I

0.1 part by weight of wetting agent, an 78.9 parts by weight of-water 1 1:

and padded to about wet pickup, I. I

(g) drying the padded.cellulosic textile for I at 60 C., and

(h) curing the dried eellulosic textile for 6 minutes at:

C. I 2. The crosslinked polymer textile product produced by the process of Claiml. Referencescited I UNITED STATES PATENTS- 3,666,400 T S/1972 Lofton'et-alx:

W LLIAM D. MART N, rr'ii ai'j i sans? ,U. xix.

8820, Dig. 18; 117--56, 76 T, 93.31,118, 139.4, 161 UB textile to a moisture content of acrylic of dimethyloldihydroxy ethyl- -.cotton-poly(methacrylic co-, 

